JP2021134875A - Planetary gear transmission device - Google Patents

Abstract

To impart holding torque without affecting a structure of a motor to be combined, or the like, in a planetary gear transmission device.SOLUTION: A planetary gear reducer 100 comprises: a cylindrical internal gear part 1 having an internal gear 1a formed on the inner peripheral surface; a planetary gear 12 that meshes with the internal gear 1a, and auto-rotates and revolves around a central axis C of the internal gear 1; a sun mounting plate 13 that rotatably supports the planetary gear 12, and is rotatably provided around the central axis C; a lower plate 3 arranged at the end part of the internal gear part 1 in the direction of the central axis C; and a thrust washer 4 arranged between the lower plate 3 and the planetary gear 12. The planetary gear 12 and the thrust washer 4 are magnetized so that the planetary gear 12 and the thrust washer 4 are magnetically attracted to each other and come into contact with each other.SELECTED DRAWING: Figure 3

Description

The present invention relates to a planetary gear transmission device.

Some electric motors have a structure in which the shaft is maintained in a stopped state by a certain holding torque when the rotation of the shaft is stopped (see, for example, Patent Document 1).

The electric motor described in Patent Document 1 has a structure in which a compression spring is provided inside a case (frame assembly) in which a rotor and a stator are incorporated. Then, the elastic force of the compression spring presses the rotor against the bearing portion, and the frictional force generated between the rotor and the bearing portion generates a holding torque at the time of stopping.

Japanese Unexamined Patent Publication No. 2017-118777

By the way, if the motor is provided with a holding torque applying portion, the structure of the motor may be complicated and the structure of the motor may be affected. On the other hand, when a planetary gear transmission device such as a speed reducer is combined with a motor, the holding torque can be applied without affecting the structure of the motor by applying the holding torque to the planetary gear transmission device instead of the motor. ..

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a planetary gear transmission device capable of applying a holding torque without affecting the structure of a motor or the like to be combined.

The present invention rotates a tubular internal gear portion having an internal gear formed on the inner peripheral surface, a planetary gear that meshes with the internal gear and revolves around the axis of the internal gear portion, and the planetary gear. Between the planetary carrier that is freely supported and rotatably provided around the axis, the end plate arranged at the axial end of the internal gear portion, and the end plate and the planetary gear. A planetary gear transmission device comprising an arranged thrust washer, wherein at least the planetary gear and the thrust washer are magnetized so that the planetary gear and the thrust washer are magnetically attracted to each other and brought into contact with each other.

According to the planetary gear transmission device according to the present invention, the holding torque can be applied without affecting the durability of the combined motor or the like.

It is an exploded perspective view of the planetary gear reducer which is one Embodiment of the planetary gear transmission device which concerns on this invention. FIG. 3 is a vertical cross-sectional view of the surface including the output shaft of the planetary gear reducer shown in FIG. 1. It is a schematic diagram which shows the magnetizing state of each component part of the planetary gear speed reducer shown in FIG.

Hereinafter, an embodiment of the planetary gear transmission device according to the present invention will be described with reference to the drawings.

<Structure>
FIG. 1 is an exploded perspective view of a planetary gear reducer 100 according to an embodiment of the planetary gear transmission device according to the present invention, and FIG. 2 is a vertical cross section of the planetary gear reducer 100 shown in FIG. 1 with a surface including an output shaft 30. FIG. 3 is a schematic view showing a magnetized state of each component of the planetary gear reducer 100 shown in FIG.

The planetary gear speed reducer 100 (hereinafter referred to as a speed reducer 100) according to an embodiment of the present invention combines two sets of planetary gear mechanisms to reduce the input rotation in two stages and output it.

As shown in FIG. 1, the speed reducer 100 includes an internal gear portion 1, three first planetary gears 12, a sun mounting plate 13 (planetary carrier), three planet shafts 14, and a sun gear 15. Three second planetary gears 22, an output mounting plate 23 (planetary carrier), three planetary shafts 24, an output shaft 30, a lower plate 3 (end plate), a thrust washer 4, and a lid 2. , With radial bearings 41, 42.

The internal gear portion 1, the lower plate 3, and the lid portion 2 are the first planetary gear 12, the sun mounting plate 13, the planet shaft 14, the sun gear 15, the second planet gear 22, the output mounting plate 23, and the output shaft 30. Also serves as an exterior for accommodating the thrust washer 4 and the radial bearings 41 and 42 inside. The internal gear portion 1 is formed in a cylindrical shape, and an internal gear 1a that meshes with the first planetary gear 12 and the second planetary gear 22 is formed along the inner peripheral surface of the cylinder.

The lower plate 3 is fixed to one end of the cylinder of the internal gear portion 1. The lower plate 3 has a boss portion 3a and a flange portion 3b. The boss portion 3a is fitted to the inner peripheral surface of the cylinder of the internal gear portion 1. The flange portion 3b is formed so as to extend outward in the radial direction from the outer circumference of the boss portion 3a and covers one end surface of the cylinder of the internal gear portion 1. An opening 3c penetrating along the central axis C is formed in the central portion of the boss portion 3a.

The thrust washer 4 has a disk shape with an outer diameter smaller than the inner peripheral surface of the internal gear portion 1, and an opening 4c having a size capable of passing the output gear 120 of the external motor is formed in the center. The thrust washer 4 is arranged inside the internal gear portion 1 with respect to the lower plate 3 with a slight gap from the lower plate 3. The outer shape of the thrust washer 4 may be, for example, a triangle or a quadrangle instead of a circle.

The lid portion 2 is fixed to the other end face side of the cylinder of the internal gear portion 1. The lid portion 2 also has a boss portion 2a and a flange portion 2b, similarly to the lower plate 3. The boss portion 2a is fitted to the inner peripheral surface of the cylinder of the internal gear portion 1. The flange portion 2b is formed so as to extend outward in the radial direction from the outer circumference of the boss portion 2a and covers the other end surface of the cylinder of the internal gear portion 1. An opening 2c penetrating along the central axis C is formed in the central portion of the boss portion 3a.

The sun mounting plate 13 is arranged on the side opposite to the lower plate 3 with the thrust washer 4 in the central axis C direction. The sun mounting plate 13 is a carrier of the planetary gear 12, and is formed in a disk shape having a diameter smaller than the inner peripheral surface of the internal gear portion 1. Three planetary shafts 14 extending parallel to the central axis C of the sun mounting plate 13 and projecting toward the lower plate 3 are press-fitted into the sun mounting plate 13. The planetary shaft 14 does not displace with respect to the sun mounting plate 13. The planetary shaft 14 may be integrally formed with the sun mounting plate 13.

The three planetary axes 14 are provided at equal angular intervals (120 [degrees] intervals) around the central axis C. A first planetary gear 12 is attached to each planetary shaft 14. The planetary shaft 14 is loosely fitted to the planetary gear 12, and the planetary gear 12 is rotatable around the planetary shaft 14 and can be displaced in the axial direction of the planetary shaft 14. When the planetary gear 12 is displaced in the axial direction of the planetary shaft 14, the planetary gear 12 may come into contact with the thrust washer 4.

A sun gear 15 projecting toward the lid 2 is fixed to the center of the sun mounting plate 13, and the sun gear 15 rotates around the central axis C integrally with the sun mounting plate 13. The sun gear 15 does not displace with respect to the sun mounting plate 13. The sun gear 15 may be integrally formed with the sun mounting plate 13.

The three planetary gears 12 fitted to the planetary shaft 14 each mesh with the internal gear 1a. A space is formed in the central portion surrounded by the three planetary gears 12. Then, as shown in FIG. 2, the output gear 120 provided at the tip of the rotating shaft 110 of the external motor inserted into this space from the outside of the speed reducer 100 through the opening 3c formed in the lower plate 3. Engage with the three planetary gears 12 at the same time.

The three planetary gears 12, the internal gear 1a, the sun mounting plate 13, the planetary shaft 14, and the sun gear 15 constitute the first planetary gear mechanism. Therefore, the rotation of the output gear 120 meshing with the planetary gear 12 is decelerated to output the rotation of the sun gear 15.

The output mounting plate 23 is arranged closer to the lid 2 than the sun mounting plate 13. The output mounting plate 23 is a carrier of the planetary gear 22, and is formed in a disk shape having a diameter smaller than the inner peripheral surface of the internal gear portion 1. The output mounting plate 23 is press-fitted with three planetary shafts 24 that extend parallel to the central axis C of the output mounting plate 23 and project toward the sun mounting plate 13. The planetary shaft 24 does not displace with respect to the output mounting plate 23. The planetary shaft 24 may be integrally formed with the output mounting plate 23.

The three planetary axes 24 are provided at equal angular intervals (120 [degrees] intervals) around the central axis C. A second planetary gear 22 is attached to each planetary shaft 24. The planetary shaft 24 is loosely fitted to the planetary gear 22, and the planetary gear 22 is rotatable around the planetary shaft 24 and can be displaced in the axial direction of the planetary shaft 24.

The output shaft 30 is formed with one end portion 31, an intermediate portion 32, a large diameter portion 33, and an output end portion 34 in this order from the side closer to the output mounting plate 23 along the central axis C. The one end portion 31 has the smallest diameter in the output shaft 30, and then the intermediate portion 32 has the smallest diameter. The large diameter portion 33 has the largest diameter in the output shaft 30.

One end 31 of the output shaft 30 is fixed to the central portion of the output mounting plate 23, and the output shaft 30 rotates integrally with the output mounting plate 23 around the central shaft C. The output shaft 30 does not displace with respect to the output mounting plate 23. The output shaft 30 may be integrally formed with the output mounting plate 23.

The three planetary gears 22 fitted to the planetary shaft 24 each mesh with the internal gear 1a. A space is formed in the central portion surrounded by the three planetary gears 22. Then, the sun gear 15 is inserted into this space, and the sun gear 15 and the three planetary gears 22 are simultaneously meshed with each other.

One end 31 of the output shaft 30 is fixed to the output mounting plate 23 through the opening 2c formed in the lid 2. Two radial bearings 41 and 42 are coaxially fixed to the opening 2c of the lid portion 2. The intermediate portion 32 of the output shaft 30 is supported by the inner rings of the radial bearings 41 and 42, so that the intermediate portion 32 can rotate around the central axis C with respect to the lid portion 2.

The large diameter portion 33 and the output end portion 34 are exposed to the outside of the lid portion 2, and the large diameter portion 33 is abutted against the inner ring of the radial bearing 42 to be positioned in the central axis C direction. ing.

The three planetary gears 22, the internal gear 1a, the output mounting plate 23, the planetary shaft 24, and the output shaft 30 form a second planetary gear mechanism. Therefore, the planetary gear 22 that meshes with the rotating sun gear 15 revolves around the central axis C while rotating in a state of meshing with the internal gear 1a, and this revolution rotates around the central axis C around the output mounting plate 23. Then, the output shaft 30 is rotated around the central axis C. At this time, the rotation speed of the output shaft 30 is slower than the input rotation speed of the sun gear 15, and the rotation speed is reduced.

That is, in the speed reducer 100 of the present embodiment, since the first planetary gear mechanism and the second planetary gear mechanism are connected in series, the rotation of the motor input from the output gear 120 to the speed reducer 100 Is decelerated by the first planetary gear mechanism and further decelerated by the second planetary gear mechanism, so that the speed is reduced in two stages and the output shaft 30 is rotated.

Here, the internal gear portion 1 and the lid portion 2 described above are made of brass, which is an example of a non-magnetic material. On the other hand, the output shaft 30, radial bearings 41, 42, output mounting plate 23, planetary shaft 24, second planetary gear 22, sun gear 15, sun mounting plate 13, planetary shaft 14, first planetary gear 12, thrust washer. Both the 4 and the lower plate 3 are made of a metal which is an example of a hard magnetic material.

In particular, the thrust washer 4 and the lower plate 3 are made of stainless steel (ferritic stainless steel or martensitic stainless steel), which is an example of a hard magnetic material.

In the speed reducer 100 of the present embodiment, the direction of the magnetic field is along the central axis C direction, and as a whole, the output end 34 side of the output shaft 30 is the north pole, and the lower plate 3 is the side far from the thrust washer 4 is the south pole. It is magnetized so that it becomes. The direction of magnetization may be such that the north and south poles are opposite to those in the above embodiment.

As a result, as shown in FIG. 3, the speed reducer 100 has components (output shaft 30, radial bearings 41, 42, output mounting plate 23, planetary shaft 24, second planetary gear 22, and so on. The sun gear 15, the sun mounting plate 13, the planetary shaft 14, the first planetary gear 12, the thrust washer 4 and the lower plate 3) are each component, with the left side in the figure being the north pole and the right part in the figure being the south pole. It is magnetized.

For example, the output shafts 30 and the planetary shafts 14 and 24 are compared with the radial bearings 41 and 42, the output mounting plates 23, the planetary gears 12 and 22, the sun gears 15, the sun mounting plates 13, the thrust washer 4 and the lower plate 3. For example, the radial bearings 41, 42, the planetary gears 12, 22, the sun gear 15, the thrust washer 4 and the lower plate 3 are magnetized with a larger magnetic force than the sun mounting plate 13 and the output mounting plate 23. Has been done.

That is, the output shaft 30 and the planetary shafts 14 and 24 are magnetized with a relatively large magnetic force (for example, 20 [gauss] or more), and the sun mounting plate 13 and the output mounting plate 23 have a relatively small magnetic force (for example, 20 [gauss] or more). Magnetized by 1 [Gauss] or more and less than 10 [Gauss]), the radial bearings 41, 42, planetary gears 12, 22, sun gear 15, thrust washer 4, and lower plate 3 have relatively intermediate magnetic forces (for example, 10). It is magnetized at [Gauss] or more and less than 20 [Gauss]).

The relative magnitude of the magnetic force of these components is not limited to the magnitude relationship described above.

Due to the above-mentioned magnetization, the speed reducer 100 generates a magnetic field attracted between the adjacent components in the central axis C direction, and a holding force is generated between the adjacent components.

Specifically, mainly between the planetary gear 22 and one end 31 of the output shaft 30, between the sun gear 15 and one end 31 of the output shaft 30, and between the planetary gear 22 and the output mounting plate 23. Magnetic between the planetary gear 12 and the sun gear 15, between the planetary gear 12 and the sun mounting plate 13, between the thrust washer 4 and the planetary gear 12, and between the thrust washer 4 and the lower plate 3, respectively. The planetary gears 12, 22 and the like that generate an attractive force and can be displaced with respect to the central axis C direction are moved to one of the central axis C directions.

In particular, the thrust washer 4 and the planetary gears 12 are in contact with each other due to the suction force generated between the thrust washer 4 and the planetary gears 12. Then, the thrust washer 4 rotates together with the planetary gear 12 in the rotation direction of the planetary gear 12 (rotational direction around the sun gear 15), but since each planetary gear 12 rotates, each planetary gear 12 and the thrust washer 4 rotate. A frictional force is generated due to the relative displacement between the gear and the gear.

The speed reducer 100 generates a holding torque that prevents the rotation of the output shaft 30 and tries to hold it in a stopped state by the above-mentioned magnetic attraction force and frictional force, so that the output shaft 30 unintentionally rotates. It can be prevented or suppressed.

Further, the speed reducer 100 has at least the thrust washer 4 and the planetary gear 12 magnetized so that the central axis C is in the vertical direction (the lower plate 3 is at the lower end). Even if the central axis C is aligned in the horizontal direction, the two are in contact with each other due to the magnetic attraction. Therefore, the holding torque can be kept substantially constant regardless of the attitude difference of the speed reducer 100.

On the other hand, in the speed reducer in which the thrust washer 4 and the planetary gear 12 are not magnetized (not the embodiment of the present invention), the central axis C is aligned in the vertical direction (the lower plate 3 is at the lower end). In the posture (), the planetary gear 12 descends due to its own weight and comes into contact with the thrust washer 4. However, in the posture in which the central axis C is aligned in the horizontal direction, the planetary gear 12 and the thrust washer 4 come into contact with each other. The condition is not stable. Therefore, the holding torque increases or decreases depending on the posture difference, and the holding becomes unstable.

Further, it is not necessary to provide a structure for generating the holding torque in the motor or other transmission device used in combination with the speed reducer 100 by generating the holding torque in the speed reducer 100.

Therefore, a motor or a transmission device that does not have a structure for generating a holding torque, which is used in combination with the speed reducer 100, is compared with a motor or a transmission device that has a structure for generating a holding torque. , The structure can be simplified.

In the speed reducer 100 of the present embodiment, the lower plate 3 adjacent to the thrust washer 4 is also magnetized, but the planetary gear transmission device according to the present invention can contact the revolving and rotating planetary gears with the planetary gears. The lower plate 3 does not have to be magnetized as long as the thrust washer arranged in is at least magnetized.

However, in the speed reducer 100 in which the lower plate 3 is also magnetized together with the thrust washer 4, a suction force is likely to be generated between the thrust washer 4 and the lower plate 3, and a larger holding torque can be generated. It is more preferable that the lower plate 3 is also magnetized together with the thrust washer 4.

In the speed reducer 100 of the present embodiment, since the internal gear portion 1 is made of a non-magnetized material (for example, brass), unnecessary substances such as chips of magnetic material are formed on the outer periphery of the internal gear portion 1. It can be prevented from adhering.

The speed reducer 100 of the present embodiment has three planetary gears 12 and 22, respectively, but the number of planetary gears 12 and 22 may be one or more, and may be two. It may be four or more, or five or more. Further, the number of the planetary gears 12 and the number of the planetary gears 22 may be the same or different.

The speed reducer 100 of the present embodiment has two planetary gear mechanisms, but the planetary gear transmission device according to the present invention may include only one planetary gear mechanism or three. It may be provided with the above planetary gear mechanism.

The speed reducer 100 of the present embodiment is a planetary gear transmission device that reduces the output with respect to the input, but the planetary gear transmission device according to the present invention is a planetary gear transmission device that accelerates the output with respect to the input. It may be a planetary gear transmission device in which the input and the output have the same speed.

1 Internal gear 1a Internal gear 3 Lower plate 4 Thrust washer 12 First planetary gear 13 Sun mounting plate 14 Planetary shaft 15 Sun gear 100 Planetary gear reducer 110 Rotating shaft 120 Output gear C Central shaft

Claims (4)

A tubular internal gear part with an internal gear formed on the inner peripheral surface,
A planetary gear that meshes with the internal gear and revolves around the axis of the internal gear portion.
A planetary carrier that rotatably supports the planetary gear and is rotatably provided around the axis.
An end plate arranged at the axial end of the internal gear and
A thrust washer arranged between the end plate and the planetary gear is provided.
A planetary gear transmission device in which at least the planetary gear and the thrust washer are magnetized so that the planetary gear and the thrust washer are magnetically attracted to each other and brought into contact with each other. The planetary gear transmission device according to claim 1, wherein the thrust washer is made of stainless steel. The planetary gear transmission device according to claim 1 or 2, wherein the end plate is magnetized so that the end plate and the thrust washer are magnetically attracted to each other. The planetary gear transmission device according to claim 3, wherein the end plate is made of stainless steel.

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